Display screen or portion thereof with a medical charting user interface



The sole FIGURE is a front view of a display screen or portion thereof with a medical charting user interface.

The broken lines showing portions of the display screen or portion thereof with a medical charting user interface form no part of the claimed design. The horizontal dash-dash and diagonal dash-dash lines within the first column of horizontal rectangles form a part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with a medical charting user interface, as shown and described. 